Use of a super-cooled fluid in lens processing

Abstract

The present invention is a process for extracting pre-polymer from a polymer lens. The process comprises the step of contacting the lens with a super-cooled solvent for a period of time to increase the modulus of the contact lens. Thereafter the contact lens undergoes additional dry processing steps. By way of example, the dry processing steps include but are not limited to surface treatment, lens coating and polishing and/or edging of the contact lens.

1 . A process for finishing a contact lens comprising the steps of: 
 providing a contact lens;    contacting the contact lens with a super-cooled fluid to increase the modulus of the contact lens; and    finishing the edge of the contact lens.    
     
     
         2 . The process of  claim 1 , wherein the pre-polymer is a silicone containing pre-polymer.  
     
     
         3 . The process of  claim 1 , wherein the pre-polymer is a hydrophilic pre-polymer.  
     
     
         4 . The process of  claim 1 , wherein at least one pre-polymer is selected from the group consisting of amide monomers such as N,N-dimethylacrylamide and N,N-dimethylmethacrylamide; cyclic lactam monomers such as N-vinyl-2-pyrrolidone; (meth)acrylated alcohol monomers, such as 2-hydroxyethylmethacrylte and 2-hydroxyethylacrylate; (meth)acrylated poly(alkene glycol) monomers, such as poly(diethylene glycol) monomers of varying chain length containing monomethacrylate or dimethacrylate; hydrophilic vinyl carbonate monomers; hydrophilic vinyl carbamate monomers; and hydrophilic oxazolone monomers.  
     
     
         5 . The process of  claim 1 , wherein the contacting occurs for a period of time that is a minimum of about 0.1 seconds to a maximum of about 20 seconds.  
     
     
         6 . The process of  claim 1 , wherein the contacting occurs by immersing the contact lens in a bath containing the super-cooled fluid.  
     
     
         7 . The process of  claim 1 , wherein the contacting occurs by spraying the super-cooled fluid over the contact lens.  
     
     
         8 . The process of  claim 1 , wherein the super-cooled fluid is at a temperature below minus 40° C.  
     
     
         9 . The process of  claim 1 , wherein the super-cooled fluid is selected from the group consisting essentially of nitrogen, argon, helium, air and carbon dioxide.  
     
     
         10 . The process of  claim 1 , wherein the step of contacting occurs after the contact lens is removed from a mold that forms the contact lens.  
     
     
         11 . The process of  claim 1 , wherein the step of contacting occurs while the lens is being released from a mold that forms the contact lens.  
     
     
         12 . A process for making a contact lens, the process comprising the steps of: 
 providing a mold comprising an anterior mold half and a posterior mold half;    filing the mold with a pre-polymer;    curing the pre-polymer to form a contact lens;    separating the anterior mold half from the posterior mold half;    removing the contact lens from one of the anterior mold half or the posterior mold half;    contacting the contact lens with a cryogenic solvent to increase the modulus of the contact lens; and    performing an additional dry processing step selected from the group consisting of coating the lens or surface treating the lens.    
     
     
         13 . The process of  claim 12 , wherein the additional dry processing step comprises finishing the edge of the contact lens.  
     
     
         14 . The process of  claim 12 , wherein the additional dry processing step comprises surface treating the contact lens.  
     
     
         15 . The process of  claim 12 , wherein the additional dry processing step comprises coating the contact lens.  
     
     
         16 . The process of  claim 12 , wherein the pre-polymer is a silicone containing pre-polymer.  
     
     
         17 . The process of  claim 12 , wherein the pre-polymer is a hydrophilic pre-polymer.  
     
     
         18 . The process of  claim 12 , wherein at lest one pre-polymer is selected from the group consisting of amide monomers such as N,N-dimethylacrylamide and N,N-dimethylmethacrylamide; cyclic lactam monomers such as N-vinyl-2-pyrrolidone; (meth)acrylated alcohol monomers, such as 2-hydroxyethylmethacrylte and 2-hydroxyethylacrylate; (meth)acrylated poly(alkene glycol) monomers, such as poly(diethylene glycol) monomers of varying chain length containing monomethacrylate or dimethacrylate; hydrophilic vinyl carbonate monomers; hydrophilic vinyl carbamate monomers; and hydrophilic oxazolone monomers.  
     
     
         19 . The process of  claim 12 , wherein the contacting occurs for a period of time that is a minimum of about 0.1 seconds to a maximum of about 20 seconds.  
     
     
         20 . The process of  claim 12 , wherein the contacting occurs by immersing the contact lens in a bath containing the super-cooled fluid.  
     
     
         21 . The process of  claim 12 , wherein the contacting occurs by spraying the super-cooled fluid over the contact lens.  
     
     
         22 . The process of  claim 12 , wherein the super-cooled fluid is at a temperature below minus 40° C.  
     
     
         23 . The process of  claim 12 , wherein the super-cooled fluid is selected from the group consisting essentially of nitrogen, argon, helium, air and carbon dioxide.  
     
     
         24 . The process of  claim 12 , wherein the step of contacting occurs after the contact lens is removed from a mold that forms the contact lens.  
     
     
         25 . The process of  claim 12 , wherein the step of contacting occurs while the lens is being released from a mold that forms the contact lens.  
     
     
         26 . The process of  claim 12 , wherein the step of contacting the contact lens occurs before the step of removing but after the step of curing.  
     
     
         27 . A process for manufacturing a contact lens, comprising the steps of: 
 forming the contact lens in a mold;    removing the contact lens from the mold;    contacting the contact lens with a cryogenic solvent to increase the modulus of the contact lens; and    performing additional dry processing steps.    
     
     
         28 . The process of  claim 27 , wherein the additional dry processing step comprises coating the contact lens.  
     
     
         29 . The process of  claim 27 , wherein the pre-polymer is a silicone containing pre-polymer.  
     
     
         30 . The process of  claim 27 , wherein the pre-polymer is a hydrophilic pre-polymer.